1. Field of the Invention
This invention relates to a system for storing and drying a mixture comprising a solid and a liquid. In particular, this invention relates to a system for transporting a slurry, separating a portion of the liquid from the slurry, and distributing the remaining slurry concentrate to a semi-circular pile for subsequent liquid evaporation.
2. Description of the Prior Art
Mining operations for solid materials such as phosphates, coal and sand are increasingly employing transportation systems whereby the mined solid is suspended in a fluid, thus producing a slurry. In some circumstances the slurry is produced to facilitate the transportation of the solid material, whereas in other circumstances the mining operation recovers the solid material already suspended in a liquid. In either case, the slurry is easily pumped through ordinary pipes for subsequent distribution and storage. The normal method involves the storage of the slurry in a large pool which allows the radiant energy of the sun to evaporate the liquid, thereby leaving the dried solid material. The solid material must then be removed from the evaporating pools and transported to a storage area. This system requires extra machinery to remove the solid material from the evaporating pools and to transport the solid material to the storage area. Furthermore, during the transportation of the material to the storage area and during the period of storage, a significant portion of the stored dried material is lost due to wind erosion and scattering.
The present invention avoids many of these problems by eliminating the remotely located intermediate evporating step. According to the present invention the slurry containing the solid material is pumped directly to the storage area whereupon it passes through the support arms of an elevated boom to a separator which is mounted at the distended end of the boom. Prior to entering the separator the slurry consists of from 0 to 35 percent solids by weight. A separator, such as hydrocyclone separator, is capable of separating solid material larger than 200 mesh from the slurry, thus yielding a slurry concentrate having from 70 to 80 percent solids. This slurry concentrate is then expelled from the separator and stored in piles for drying. The elevated boom is pivotally mounted at its base allowing the separator to sweep an arc of a semi-circle, thereby producing a storage pile having a much greater length and concommitant storage volume than the ordinary pole mounted separator. The relatively high solid content of the concentrated slurry discharged from the hydrocyclone separator allows the solid material to be stored in piles having an angle of repose approaching 45 degrees without excessive flushing due to excessive liquid content. Furthermore, the transportation and storage of the solid material in a slurry drastically reduces the losses of the solid material during transportation. Also, the storage of the solid material in a slurry initially reduces the erosion losses since subsequent slurry depositions cover and re-wet the drying solid material.